Effect of Frost Change on Transplanting Time of Flue-cured Tobacco in Northwest Fujian

Using the meteorological data from January to April of 11 counties in northwest Fujian in the past 37 years, temporal and spatial distribution characteristics and change patterns of frost during flue-cured tobacco transplanting period in northwest Fujian were analyzed with the modern climatic statistical diagnostic tools, aiming to provide reference for proper transplanting time of flue-cured tobacco.The results showed that:(1) Frost days in different regions and frost injury days in different degrees showed a slowly decreasing trend, and frost days of northwest were significantly more than southeast, large range of frost may still occur in early March.(2) Last frost date showed a slowly advancing trend, and the average last frost date was between February 11 and March 08, later than flue-cured tobacco transplanting time.(3) M-K test showed that the long-term change trend of frost days was a decreasing trend.Although there were 3 periods of sudden changes, they did not change the decreasing trend.In summary, this work provides a good basis for advancing the transplanting time of flue-cured tobacco properly, based on that frost days are becoming less and last frost date is advancing.The northwest should be appropriately cautious on advancing the transplanting time, while the southeast can advance properly.The tobacco plants however should be protected from frost damage by the way of mulching, moderate deep planting and vegetative soil transplanting.